Vision Screening Online Training Program

Module 1: Introduction

Objectives:
After reading these modules, the participant will be able to:

  • Describe the importance of vision screening and early identification
  • Identify the Child and Teen Checkups (C&TC) vision screening procedures for children and youth ages 0 through 20 years
  • Differentiate between the subjective and objective components of the vision screening
  • Document vision screening results

Discussion:

The purpose of vision screening
In the childhood years it is important to detect any vision problems that may impair a child’s ability to learn. The screening process can help determine which infants and children may need further diagnostic assessment and referral to a vision professional.

When To Screen
Vision screening should be performed on a regular basis during infancy and childhood (Click here for Periodicity Schedule).

Subjective screening is provided at nine visits before age 3 years and is based upon the child's medical history. Taking a good visual history when a child is seen for 'checkups' is important because many eye conditions are hereditary. Often, a referral to an eye specialist may be based on vision history alone.

Much of the vision screening in the age group of age 3 years and younger is often provided by the health care provider as part of the physical exam.

Who should screen?
In the Child and Teen Checkups program, the components of vision screening are provided by both the health care provider (HCP - definition includes physician, nurse practitioner, physician's assistant, or registered nurse [RN] with training in vision screening from MDH) and the medical assistant or licensed practical nurse (LPN). For example, the vision health history, the muscle balance screening (observation, corneal light reflex, cross cover and external ocular movements [also called fix and follow]), red reflex and pupillary light response are performed by the HCP. Screening with visual acuity charts and stereo acuity test is often conducted by the medical assistant or LPN. For more information regarding C&TC roles, visit the following links.

Child and Teen Checkups Fact sheets:

Screening is also provided in Minnesota for Early Childhood Screening for public school entry (legislative mandate), in schools (non mandatory), and in Head Start programs. This web training module for vision screening has been developed to educate those who will be screening from each of these areas. In regards to C&TC screening, each of the screening procedures in this training module indicate whom is the most appropriate to administer the screening tests.

Why Vision Screening is important!
It is estimated that 80% of learning comes through the visual senses [1]. Vision affects the performance of the whole child. Vision also influences the child’s performance and adjustment in school, society, and influences overall health [2]. Vision screening is important because it leads to the identification of children with vision abnormalities such as visual acuity and muscle balance problems.

Children with impaired vision often are not aware of their impairment; therefore, they do not complain or seek help. If they have always seen things in a blurred or distorted way, they accept the imperfect image without question. It is up to adults responsible for children’s health care and educational development to detect children experiencing vision problems.

What kind of vision problems are we screening for?
In infants and toddlers, it is important to screen the child’s eyes with an ophthalmoscope to make sure that the eye orbit and structure is healthy and that there are not any defects such as cataracts or tumors present (this is usually performed by the provider in C&TC programs) [3]. In addition, some children in this age category may have significant visual acuity problems such as excessive farsightedness, however, farsightedness is a normal condition for children under the age of 5 years old [4]. Young children may also have strabismus (crossed eyes). This too needs to be evaluated by an eye professional to prevent amblyopia (lazy eye).

The eye is not fully developed until after the age of 8 years old [5]. Before full visual development is reached, it is very important to screen for amblyogenic (lazy eye) risk factors. These are conditions that may result in amblyopia (lazy eye) if not detected and treated early [6].

Conditions include:

  • Organic defects (congenital cataracts [cloudy eye lens], ptosis [droopy eye lid])
  • Strabismus (muscle imbalance)
  • Anisometropia (a difference in visual acuity of each eye)
  • Refractive errors (being nearsighted, farsighted, or having astigmatism (distorted vision at both near and far)).  
The earlier these problems are detected and treated, the better the outcome.

Generally, nearsightedness first occurs in school-age children. Because the eye continues to grow during childhood, it typically progresses until about age 20 [5]. Once children reach puberty, about 20% of children may develop nearsightedness; this too will require referral to an eye specialist [5].

Throughout all these years, it is also important to protect the eyes from injury from the sun or sports and play too.

How is a child affected by vision loss?
If it is a visual acuity problem, a child with near-sightedness (myopia) will not see objects at a distance well. On the other hand, a child with farsightedness (hyperopia) will not see objects well at close distances. If the child has astigmatism, they will see things blurry, whether the image that they are looking at is near or far.

Any condition that prevents both eyes from working as a team (i.e. having the ability to bring the objects seen with each eye into one image) during the first decade of life can cause lazy eye (amblyopia). The detection of amblyopia at an early age is a very important aspect of the routine eye examination in the pediatric population. Left undetected and untreated, amblyopia may lead to irreversible visual deficits, especially permanent problems related to depth perception and the ability to see three dimensionally. Therefore, early identification and referral to an eye doctor is extremely important.

Vision Screening Tips
In young children (i.e., less than age 5) it is important to screen efficiently with a steady pace due to children’s limited attention span. It is also very helpful to have several toys or attention grabbers. Try to make the vision screening a fun event for the child. For optimal screening, make every effort to minimize distractions in the screening environment. If screening is done in a large room, one method of minimizing distractions would be to have a curtain separating the children being screened.

Children who are familiar with screening will move through a screening procedure with more ease in comparison to children who are encountering a screening event or test for the first time. In regards to specific screening tests, it is possible to condition the child beforehand for individual tests. For example, there are puzzles and preparation charts available for visual acuity tests in the 2007 Minnesota Vision Screening Training Manual (click on the "Vision Screening Information" link in the column on the right side of this page to access the 2007 Manual). The visual acuity test is often the most time consuming during screening, so if conditioning the child to the tests is possible, screening times generally improve.

Workgroup
The recommendations contained in this module were developed in 2007 with the advice of 14 vision screening experts and key stakeholders who were selected by their respective professional organizations or agencies in Minnesota because of their knowledge and interest in vision screening for children. The recommendations were further revised in 2009. Following a comprehensive MDH literature review of vision screening research and practice, the workgroup addressed issues that were either unclear in the literature or were conflicting between professional organizations. A listing of organizations represented and workgroup members can be found in the Vision Screening Procedures for Infancy, Childhood and School Age Children Training Manual (click on the "Vision Screening Information" link in the column on the right side of this page to access the 2007 Manual).  Throughout the module, the recommendations of this workgroup will be presented and may be referenced as the "Minnesota Vision Screening Procedures".

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